The disgruntled ex-LAPD officer suspected of shooting three police officers this morning and killing a couple in Irvine earlier this week tried to steal a boat in San Diego and flee to Mexico, authorities said.

Police officials said they believed Christopher Jordan Dorner, 33, attempted to steal a boat from an elderly man about 10:30 p.m. Wednesday at the Southwestern Yacht Club in Point Loma, hours before the police shootings in Riverside.

The 81-year-old boat owner reported being accosted and tied up by a burly man who threatened him with a gun and said he wanted the boat to flee to Mexico.

But while the assailant was trying to start the boat, a rope became entangled in the propeller and the boat was inoperable, authorities said.

The suspect took the boat owner’s cell phone and fled the scene and the boat owner was unharmed.

About 2 a.m., a citizen reported finding property belonging to Dorner on a street near Lindbergh Field, not far from the scene of the attempted boat theft. The property included a briefcase and Dorner’s LAPD badge.

San Diego police are on maximum deployment in search of Dorner.

The California Highway Patrol has issued a "blue alert" for nine Southern California counties. Officials said Dorner is believed to be driving a 2005 blue or gray Nissan Titan, with California license plate 8D83987 or 7X09131. Police said they believe he may be switching between the two license plates. Dorner is described as a black male, 33 years old, 6 feet tall, weighing 270 pounds with black hair and brown eyes. His last known address is in La Palma.

Irvine police on Wednesday night named Dorner as the suspect in the weekend double slaying of Monica Quan, the Cal State Fullerton assistant basketball coach, and her fiance, Keith Lawrence, a USC campus safety officer.

Randy Quan, a retired LAPD captain, was involved in the review process that ultimately led to Dorner’s dismissal.

A former U.S. Navy reservist, Dorner was fired in 2009 for allegedly making false statements about his training officer.

The suspect posted an online manifesto on his Facebook page, threatening to harm police officials and their families, law enforcement sources said.

Authorities believe that he left San Diego and headed north.

The first shooting occurred about 1:30 a.m. in Corona, where two LAPD officers were providing protection for someone mentioned in Dorner’s manifesto, officials said. One officer suffered a grazing head wound during a shootout and Dorner fled the scene, police said.

A short time later, two Riverside officers were involved in a shooting with a suspect at the corner of Magnolia Avenue and Arlington Avenue in Riverside, according to Riverside Police Officer Bryan Galbreath. One of the police officers was killed.

"They were stopped at a red light and just ambushed," Riverside Police Lt. Guy Toussaint said.